[reset] Clean up ActivityAllAppsContainerView#reset.

Digged into the history of this part, some code is duplicated and thus removed. See https://docs.google.com/document/d/1mp1HwLhkLE_o0o_InhntFz3oIGsg94b9XucAal0IgOE/edit?tab=t.0#bookmark=id.130cyqeojzrk

ag/24198780 introduced the `MAIN_EXECUTOR.getHandler().post` part, which is still needed for logging purpose.

Bug: 328505782
Test: manual
Flag: NA
Change-Id: Ie7622c497b803f722fd734d30c4c3d9692d152c6